title: Impact of intra- and extra-osseous soft tissue composition on changes in bone mineral density with weight loss and regain.
abstract: Recent studies report a significant gain in bone mineral density (BMD) after diet-induced weight loss. This might be explained by a measurement artefact. We therefore investigated the impact of intra- and extra-osseous soft tissue composition on bone measurements by dual X-ray absorptiometry (DXA) in a longitudinal study of diet-induced weight loss and regain in 55 women and 17 men (19-46 years, BMI 28.2-46.8 kg/m(2)). Total and regional BMD were measured before and after 12.7 ± 2.2 week diet-induced weight loss and 6 months after significant weight regain (≥30%). Hydration of fat free mass (FFM) was assessed by a 3-compartment model. Skeletal muscle (SM) mass, extra-osseous adipose tissue, and bone marrow were measured by whole body magnetic resonance imaging (MRI). Mean weight loss was -9.2 ± 4.4 kg (P < 0.001) and was followed by weight regain in a subgroup of 24 subjects (+6.3 ± 2.9 kg; P < 0.001). With weight loss, bone marrow and extra-osseous adipose tissue decreased whereas BMD increased at the total body, lumbar spine, and the legs (women only) but decreased at the pelvis (men only, all P < 0.05). The decrease in BMD(pelvis) correlated with the loss in visceral adipose tissue (VAT) (P < 0.05). Increases in BMD(legs) were reversed after weight regain and inversely correlated with BMD(legs) decreases. No other associations between changes in BMD and intra- or extra-osseous soft tissue composition were found. In conclusion, changes in extra-osseous soft tissue composition had a minor contribution to changes in BMD with weight loss and decreases in bone marrow adipose tissue (BMAT) were not related to changes in BMD.
authors.affiliation: The Institute of Human Nutrition and Food Science, Christian-Albrechts University, Kiel, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Bosy-Westphal
authors.forename: Wiebke
authors.initials: W
authors.lastname: Later
authors.forename: Britta
authors.initials: B
authors.lastname: Schautz
authors.forename: Merit
authors.initials: M
authors.lastname: Lagerpusch
authors.forename: Kristin
authors.initials: K
authors.lastname: Goele
authors.forename: Martin
authors.initials: M
authors.lastname: Heller
authors.forename: Claus-C
authors.initials: CC
authors.lastname: Glüer
authors.forename: Manfred J
authors.initials: MJ
authors.lastname: Müller
mesh_terms: D015502:Absorptiometry, Photon; D052436:Adipose Tissue, White / Q000473:pathology; D000328:Adult; D001823:Body Composition; D015519:Bone Density; D001853:Bone Marrow / Q000000981:diagnostic imaging / Q000473:pathology*; D001862:Bone Resorption / Q000150:complications* / Q000000981:diagnostic imaging; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D050177:Overweight / Q000150:complications / Q000178:diet therapy* / Q000473:pathology*; D012008:Recurrence; D012727:Sex Characteristics; D015430:Weight Gain; D015431:Weight Loss; D051598:Whole Body Imaging; D055815:Young Adult